1. Field of the Invention.
The present invention relates to the processing of seismic data utilizing a tomographic process and, more particularly, but not by way of limitation, it relates to an improved method for velocity estimation of seismic data using the seismic tomography processing.
2. Brief Description of the Prior Art.
The prior art processes for ray-tracing evaluated the subsurface in terms of determinative cells of constant slowness values which were then reconstructed to approximate seismic ray paths, still other types employed finite difference ray-tracing methods. The prior types using constant slowness values for analyzing individual cell structures culminated in very severe reconstruction resolution limitations. The alternative finite difference tracing methods introduced uncertainties that make them unsuitable for iterative estimation schemes. None of the prior art types treat the field within a cell as continuous, and an assumption must be made that the cell either is constant in value or constant in the value of its gradient. This approach brings about severe limitation in terms of resolution and continuity of the reconstructed field. The prior art schemes also employ computationally expensive finite-difference ray-tracing schemes that are not always suitable for parameter adjustment algorithms and other attempts to generalize such diverse data.